1. Field of the Invention
The present invention relates to 2-methyl-{4-O-(2-amino-2-deoxy-xcex2-glucopyranosyl)-1,2-dideoxy-xcex1-glucopyrano}(2,1-d)-2-oxazoline, an acid addition salt thereof, 50% deacetylated chitin or an oligosaccharide thereof and acid addition salts thereof.
2. Background Information
Chitin, which is a biomass produced in abundance, is the straight-chain polymer of N-acetylglucosamine and obtained industrially by extracting from the outer shell of Crustacea.
However, there is no appropriate solvent for dissolving chitin, thereby making it difficult to prepare a derivative. Therefore, the application range of chitin as a raw material is narrow and its additional value is low. Since chitosan which is the deacetylated product of chitin dissolves in an acid, is very reactive and has an amino group which shows specific properties such as antifungal properties and cholesterol absorption suppression, it is easy to form derivatives from chitosan, chitosan is used in various fields, and both basic and applied research are now being carried out energetically.
Under the circumstances, it has been found that partly deacetylated chitin and a low molecular weight product thereof which are intermediates between chitin and chitosan show water solubility, high moisture retention and metal adsorption properties or high elicitor activity for plants and they are attracting much attention as a raw material having high applicability.
However, a process for producing partly deacetylated chitin is to deacetylate chitin in a concentrated alkali after it is highly swollen or to acetylate chitosan by adding a predetermined amount of acetic anhydride after it is dissolved, and hence has such a problem as the nonuniform distribution of acetyl groups and fluctuation in the quality of partly deacetylated chitin products.
When its elicitor activity for plants is subjected to an assay, it is extremely difficult to elucidate its action mechanism from the grasp of a phenomenon because a mixture of partly deacetylated chitin oligosaccharide obtained by hydrolyzing partly deacetylated chitin is used as an elicitor active substance and its structure is not uniform.
Further, substituents existent on formed partly deacetylated chitin and derivatives thereof such as oligosaccharide when a free amino group having high reactivity and residing on partly deacetylated chitin and an oligosaccharide etc. thereof is chemically modified are not aligned regularly, thereby causing differences in the quality of derivatives.
It is an object of the present invention to solve the above problems of the prior art and develop a further advanced application method for a chitin material.
The inventors of the present invention have conducted intensive studies to solve the above problems and have succeeded in the production of 2-methyl-{4-O-(2-amino-2-deoxy-xcex2-glucopyranosyl)-1,2- dideoxy-xcex1-glucopyrano}(2,1-d)-2-oxazoline which is a novel di-saccharide.
Further, they have found that 50% deacetylated chitin or an oligosaccharide thereof and salts thereof which are novel compounds can be synthesized by subjecting the compound to an enzyme catalyst addition polymerization reaction according to a known method. The present invention has been accomplished based on these facts.
The present invention concerns is 2-methyl-{4-O-(2-amino-2-deoxy-xcex2-glucopyranosyl)-1,2- dideoxy-xcex1-glucopyrano}(2,1-d)-2-oxazoline represented by the following formula (1) or an acid addition salt thereof.

The present invention also relate to a is 50% deacetylated chitin having a repeating structure represented by the following formula (2) or an oligosaccharide thereof and acid addition salts thereof.

(wherein n is an integer)